The invention relates to a fitting switching device, having a drive-output shaft and having an input shaft which is coupled to the drive-output shaft and by way of which the drive-output shaft can be driven in the normal operating mode, and having an emergency drive, wherein the drive-output shaft can be transferred from a usage position into an end position additionally by the emergency drive, wherein a recess is formed on an element which is drivable and/or driven by the emergency drive, and wherein a blocking element is movable by way of an actuating device from a position in which said locking element is disengaged from the recess into a position in which said locking element engages into the recess.
The invention also relates to a fitting control arrangement having a control drive, wherein a drive output of the control drive is operatively connected to the input shaft of a fitting switching device.
Fitting control arrangements are known and are used for the actuation of fittings, for example in industrial installations. Such fitting switching devices are for example known from technical systems in which a mass flow is subjected to open-loop or closed-loop control by way of fittings. Here, in the normal operating mode, the fittings are actuated by way of corresponding control drives. In the event of a power failure, for example in the case of an electrical power failure or in the event of a failure of a hydraulic or pneumatic supply of the control drives, the fitting switching devices serve for transferring the drive-output shaft into a predefined end position in order to transfer the respectively connected fitting into a defined end state, for example an open state or a closed state. For this purpose, the fitting switching device switches from the normal operating mode into the predefined end position in order to transfer the respectively connected fitting into a defined end state, for example an open state or a closed state. For this purpose, the fitting switching device switches from the normal operating mode into the predefined end position in the event of deviations. Since the defined end state of the respectively connected fitting is, in a common usage scenario, a closed state, the fitting switching device is also referred to as a fitting closing device.
For this purpose, it has become common for the fitting switching device to be equipped with an emergency drive which, outside the normal operating mode, ensures the transfer of the drive-output shaft into the desired end position. To prevent the emergency drive from intervening in a power flow between the input shaft and the drive-output shaft in the normal operating mode, locking devices are used which lock the emergency drive in the normal operating mode. For this purpose, an element which is drivable and/or driven by the emergency drive may have a recess into which a blocking element engages with a locking action.
EP 1 536 163 A2 has disclosed an actuator for a cable-controlled automatic gearbox, in the case of which a coil acts on a claw, wherein, in the coil, there is formed an internal return spring for disengaging the claw in the deenergized state.
U.S. Pat. No. 1,670,313A has disclosed a system of a liquid pressure control arrangement, in the case of which a claw which has two teeth is provided which can be engaged, by way of an electromagnet, into a toothing of a gearwheel, wherein a return spring is provided for the disengagement of the claw.